public void AddVariable(Variable var)
{
_variables.Add(var.Name, var);
}
/// <summary>
/// <para> Production E: </para>
/// <para> E -> N = VE' </para>
/// </summary>
/// <exception cref="CalculatorException">On syntax error</exception>
private void E()
{
if ( !SkipSpacesAndContinue() )
{
return;
}
if (!Char.IsLetter(_initialInput[_index]))
{
throw new CalculatorException("Was expecting a letter.", _index);
}
// E -> N = VE'
var name = N();
if (name == null ||
name == Variable.E.Name ||
name == Variable.PI.Name ||
name == Variable.ANS.Name )
{
throw new CalculatorException("Variable name is reserved for constant value.", _index);
}
if (name == Calculate.Root ||
name == Calculate.Log ||
name == Command ||
name == Calculate.Command ||
name == Help.Command ||
name == Fraction.Command)
{
throw new CalculatorException("Variable name is reserved for existing operation.", _index);
}
if ( !SkipSpacesAndContinue() )
{
return;
}
if (_initialInput[_index] != '=')
{
throw new CalculatorException("Was expecting '='.", _index);
}
_index++;
var value = V();
var oldVariable = Variable.GetVariable(name);
if (oldVariable != null)
{
oldVariable.Value = value;
_variablesToSet.Add(oldVariable);
}
else
{
var newVariable = new Variable(name, value);
_variablesToSet.Add(newVariable);
Variable.Variables.Add(newVariable);
}
E_();
}
